Foot attachment for pit frops or steel arches employed as colliery or mining roof supports



Sept. 1, 1931. ENsFo 1,821,020

FOOT ATTACHMENT FOR PIT PROPS OR STEEL ARCHES EMPLOYED AS COLLIER! OR MINING ROOF SUPPORTS Filed July 8, 1930 4 Sheets-Sheet l INVBNTUR THUP/IAE MENBFTEIHTH lEhy ATTURME Y Sep 1931- 'r. MENSFORTH ,821,020

FOOT ATTACHMENT FOR PIT PROPS QR STEEL ARCHES EMPLOYED AS COLLIERY OR MINING ROOF SUPPORTS Filed July 8, 1950 4 Sheets-Sheet 3 Fig.7 -Fm,.@.

Z: 3 1 i i W W v i i I l E 5 1 //4 l L J-+ i I 3 I NVEN T E! R Tf-lDNASNENSTDRTJ-L ATTEIRNEY Sept. 1, 1931. r. MENSFORTH 1,821,

FOOT ATTACHMENT FOR PIT PROPS QR STEEL ARCHES EMPLOYED A5 COLLIERY OR MINING ROOF SUPPORTS Filed July 8, 1930 4 Sheets-Sheet 4 M? mm 7 E 4%- Z 7 ggfl My gmgggfgdzz i/ 5 /5 Q /r5 i v 5 ;2/ 3%; Ziz/ N 5? 4 E 24 $0 20 5 70 ii 55;; -zzigahh gal 13 i 77 23 2S? s Y5 Y9 /1" I 9 M. Y

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L .4 y I INvE-N TU R THgJEASMENSFURIH ATTDRNEY UNITED. STATES yield or become distorted or broken.

Patented Sept. 1, 1931 PATENT OFFICE TI-IOMAS IvIENSFG- EITH, MIDDLETON ST. GEORGE, ENGLAND FOOT ATTACHMENT FOR PIT Flt-OPS 01?. STEEL .ARCHES EMPLOYED AS COLLIERY OR MZNIN ZT ROOF SUPPORTS Application filed July :8, 1920,.Seria1 'No. 486,395, and in Great Britain June 17,1929.

Thisinvention relates to steel pit props of straight or- ,arch formation employed for temporarily or permanently supporting the roof during mining and. colliery operations. It is customary when steel arches are used to place wood baulks between the arches and the overlying material so as to distribute the pressure of the, roof and walls evenly on the steel arch. WVhen a straight steel prop is used the usual crown tree is employed.

/ Hitherto it has been found after the steel props or supports have been set, a certain amount of settlement of earth takes place, thereby applying to the supportsintensepressure which is very ClilllCHlt to resist and causes the supports, in many cases, to freely The usual practice is, after a certain amount of settlement has taken place, to remove the supports and reset them thereby relieving the stress to whichthey have been subjected.

It has frequently been found that the operation of re-setting requires to be repeated owing to a number of settlements of the overlying materialtaking place, after which the said material binds itself together and the roof then remains stable for a considerable period. I l Wither-e timber props have been employed they have frcquentlybeen' pointed at one end in such a manner that they have been weakened at the saidends so-that they can yield to the applied pressure, thereby preventing the props from being overloaded and fractured. I c

y In thisinvention provision is made for dispensing with the above named re-setting operations and the expense attendant there on, by providing an end attachment for the leg or legs of the pit prop or steel arch, whereby the prop or arch automatically ad,- justs itself.tothepressure applied thereto by means of a shearing action.

7 In carrying, this invention into practice the straight proper arch is made of steel. and of H-section as is usually done, and the arch is made of horse; shoe or other a desired shape inone or more portions. When made in two Fig. 4 showing the attachment after made shorter in length than hitherto to pro vide a space for the insertion of the hereinafter described end attachment between the top of the road or wood or other sleeper, that is usually placed longitudinally there- 0n,and the lower end or ends of the said leg or legs.

When this invention is employed in combination with an ordinary steel prop the latter is made shorter in length than hitherto to allow for the end attachment to be secured to one end of the prop.

Each attachment may consist of six portions, namely, two channel sections,hereinafter termed shearing members ,and four cover or clamping plates which are arranged so that the two shearing members,- with their flanges turned in an outward direction,fit on each side of the web of the H-section steel arch or prop and between its flanges as hereinafter described.

In the drawings hereunto annexed the end attachment is shown applied to the ends of angle to Fig. ,3;

Fig. 5 a sectional plan on line'A, A, Fig 3; Fig. 6 an elevation of a modified arrange ment of the means for securing the attachnient to the end'of a straight prop orsteel arch; 1

Fig. 7 a sectional elevation drawn at a right angle to Fig. 6; Fig. 8 a sectional plan on line B, B, Fig. 6; Fig. 9 a sectional. elevation corresponding to the shearing action has taken place; Fig. 10 a sectional elevation of the attachment illustrated in Fig. 7 after the shearing action has taken place;

Fig. 11 an elevation of theshearing memher as shown inFig. 3

Fig. 1 a sectional elevation drawn at a right Fig. 12 an elevation of same member after the shearing action has taken place;

Fig. 18 an elevation of a short cover plate; 7 Fig. 14 an elevation of the'end of a straight prop or a steel arch for the reception of the securing shownin Figs. 6 to 8.

Figs. 3 to 14 inclusive are drawn to ailarger scale than Figs. 1 and 2. I

Like partsin all theviews are marked with corresponding reference numerals.

.The straight prop 1 or arch 2 is made of steel and of H-section as is usually done. The arch 2 is made of a horse shoe or other desired shape'in one or more portions whichare secured together by fish plates and bolts,

shown atFig. 2. \Vhen the arch 2 is used one 'oriboth of its legs is or aremade shorter inlength than usual to'provide a space for the insertion of the hereinafter described end attachment between the top ofthe road or wood or other sleeper 3,-that is usually placed longitndinally'thereon,-and the lower end or ends of the said leg or legs.

" The attachment consists of six portions, namely, two channel sectionshereina'fter termed shearing members 4, 4,-a-nd four cover or clamping plates marked respective 1y 5, 5, and 6,6, whichare so arranged that the two shearing members 4,"4,with their flanges 7, 7, turned in an outward directi'on,- fit on each side of web 8 of the H-section of the steelprop 1 or of the arch2 and between'its flanges. The shearing members 4, 4, aremade of such a length that they will bridge and overlap the gap between the end 9 of the straight prop 1 or of the leg of the arch 2 and a short piece of H-section' steel 10 that rests upon the said wood or other sleeper 3 or' abuts against the point of application of the load indicated by the arrow marked a Fig. 1; The shearing members 4,4, are made U-shaped, as shown at Figs, 5, 8, '11 and 12, recessed in the web portion so that the thin web 11 thus formed will easily tear under pressure, as will be presently describedglt will be found that if the :web" [-11, is Vmade, seven-thirty seconds of an inch in'thicknes's satisfactory results will be ob- 7 .tained,but itshould be distinctly understood jthatEitf not limited to thesaid size, which may vary as circumstances require. The cover plates 5,5, and 6, 6, are each made of a U-shaped section,'as shown at Figs. 5, '8, and, 13,va-daptedatofit between the flanges 7 7, of the shearing 'members4, 4, so that the longitudinal-edges of eachof the projectingportions 12, 12 of the plates abut against asuitable thickened. portion of the web of shearing member 4. The cover plates 6,

6, are preferably made shorte-r. ,butjnot nec-' ,essarily so,in. length-than the other two plates 5, 5. and the plates 6,6, are arranged one onea'ch side of the short piece of H-section steel 10, the end of which abuts against the point a'of application of the load, or

rests upon the Wood oi other sleeper 3. The

' cover plates 6, 6, shearing members 4, 4, and

short piece of H-section steel 10 are secured together by a case hardened bolt 13 provided with a square shank 14,- for a portion of 3 its length,w .hich passes through square holes 15, 1'6, 17,-as shown at'Figs. 4 and 7,- formed for its reception in the said parts, a nut 18 and spring Washer 19 being provided for securing purposes. The upperor longer cover plates 5, 5, the upper endof the shearing member 4, 4, and the end '9 of the straight prop 1 or the arch 2 are respectively provided with the holes 20, 21 and 22 through which is passed a case hardened bolt 23, 7

having a nut 24 and spring washer 25f mounted thereon,--for securing the upper ends of the channelmembers 4, 4, to the lower end 9 of the leg of the steel arch 2 or straight prop 1. The square holes 21 former in the thin i Webs 11 of the channel members 4, 4, for the reception of the top bolt 23 are each provided with an outwardly projecting lip 26 on its lower edge for enabling a start to be given to the shearing operation when pressure is applied to the steel arch 2' or the straight prop 1.

In the modified securing means for the end attachment shown at Figs. 6', 7, 8 and 10, the long cover plates 5, 5, and the upper ends of the shearing members 4, 4, are secured to the end'9 of the straight prep '1 or the steel arch 2 by means'of a metal gib or a piece of hard steel,"hereafter termed a cross piece 2 7,whi-'ch is approximately rectangular in cross section, and takes the place of the bolt 23. One edge of the cross piece 27 is inclined from end to end and the opposite edge is provided with a" V or other shaped projection 28, or about itsc'entre, which is either pointed or rounded, as shown'at Figs. '7 and 10,or otherwise shaped at the juncture of the two sides. Each of the said sides is arranged respectivelyito form a tangent to an.arc,as shown at Fig'.r7,the outer end of which terminates at a transverse rcess 29, 29 tormed at asuitable d stance trom the end of the cross piece. The transverse 'recesses'29, 29 in the cross piece 27 are arrangedat the same distance apart as are the webs of the cover plates 5, 5. A headed gib or wedge 30 is arranged to be'pl'aced upon the inclined edge of the cross piece 27, and when so placed and driven tightly into position the cross piece 27 will secure the cover plates 5,5, shearing'members 4, 4, and end 9 of the straight prop 1 orthe arch 2 together. In the web of each larger cover plate '5, as shown at Fig. -6,the rectangular hole 20 is formed of such a size that the end' of the 1 cross piece27 can pass through it; a portion ofth'e said web in which the hole 20 is formed can then enter therecess 29. The

hole 20 is. also made 01. such asize that the cross piece 27 passing through them.- The hole 22 in the end 9 is made as shown at Fig. 14 when a gib or wedge 30 and cross piece 27 is employed, that is to say, the cross piece is placed in the widest portion of the hole 22,

and the gib or wedge 30 in the narrowest portion 22% of the said hole. This arrangement prevents the parts 27 and 30 being wrongly inserted. "This type of securing means allows the lip 26, Fig. 4, to be dispensed with. Thecoverplates and shearing members are assembled together and attached to the end of a pit prop or an arch in the following manner, namely The ends of the two shearing members 4, 4,'and short cover plates 6, 6, are rigidly fixed byithe bolt 13 and nut 18 to the short piece of H section steel 10,"which is of the same contour in cross section as the end of the pit prop 1 or arch 2. The opposite ends of the shearing members 4, 4, are secured by the bolt 23, nut 24,,and washer 25, or by the cross piece 27 and wedge 30 to an end of the. pit prop 1, or of the arch2. The just named opposite end of each shearing member 4 is placed on each side ofthe web 8 and between the flanges of the end 9 with the flat portion or web ofeach shearing member 4 in contact with the central web 8 of the said end. Between the flanges 7 7, of each of the shearing members 4, 4, is placed one of the larger covering plates 5 with its flanges 12, 12 in contact with the web of the said members, as shown at Figs. 5 and 8. The last named cover plates 5, 5. are secured to the end 9 and also'to the shearing members 4, 4, by the bolt 23 an-dnut 24, or bv the cross piece 27 and wedge 30 so that both of thecover plates 5, 5, prop 1, or arch 2 and the securing means are capable of sliding whenever pressure is placed upona prop 1 or an arch 2.

Vhen the said pressure is applied by the settlement of the overlyingmaterialthe leg of the steel arch 2 or prop 1 moves in, say, a downward'direction towardsthe small piece ofH-section steel 10, thus carrying the upper case hardenedbolt 23, nut 24 and washer 25, or thewedge 30 and crosspiece 27 with it, 7 thereby tearing the thin webs 11 of the shearing members 4, 4. This tearing actioncontinues until the settlement of the earth ceases or the leg abuts against the upper end of the short piece of H-section steel 10. During the just named movement the two upper or long cover plates 5, 5, slide upon the thick portion of the, Web the shearing member 4, 4. During the iust named shearing action a narrow strip 31,Figs. 9 and 10,is torn from the thin web 11 by the downward movement of the bolt 23 or cross piece 27.

When it is desired to remove the anchor prop whilst theload is upon it, all that is necessary when across piece 27 and wedge '30 are employed, is to knock back with ahammer or other tool the projecting end ofthe gib or wedge 30, thus relieving the pressure on the arch 2 or prop 1. WVhat I claim is a 1. An end attachment for the leg portion of steel props and arches used as supports for the roots of collieries and mines, each attachment being composed of-a plurality-of portions, namely, a pair of flanged U-shaped shearing members'and four U-shaped clamping plates, the said plates being arranged in pairs at the ends of the shearing members which are afterwards attached respectively to the prop and to a footpiece formed of steel, theshearing members bridging and overlapping a gap between the end of the prop and the footpiece.

2. An end attachment for use in connection with the legs of props and arches employed for supporting roofs in collieries and mines having a pair of shearing members adapted to be fixed on each side of the end of a prop, each member being formed U-shaped in cross section and provided with a thin longitudinal central web portion having an opening therein for enabling the web to be torn on undue pressure being applied to the prop, a clamping plate arranged at each} end of a shearing member, and means for securing the shearing members and their clamping plates respectively to the end of a prop and to a footpiece as set forth.

3. An end attachment for use in connection with the legs of props and arches employed for supporting roots in collieries and mines having a pair of U-shaped shearing members, each member being provided with a thin longitudinal central web having an opening therein with a lip for enabling the web to be torn on undue pressure being ap plied, a pair of U-shaped clamping plates arranged at each end of the shearing members and between the flanges thereof, the ends of the shearing members being afterwards respectivelv fitted between the flanges of, and arranged to abut against, the webs of the end of a pit prop and a footpiece of H- section steel, the shearing members and the clampingplates being secured in position by bolts which pass transversely through openings in the said parts, the upper bolt being arranged to tear the said thin longitudinal central web on undue pressure being applied to the prop as set forth;

4. An end attachment for use in connection with the legs of props and arches employed for supporting roofs in collieries and mines having a pair of U-shaped shearing memtherein for enabling the web to be torn on sundae;prgssurer being applied,. a,spa ir zflf' U- I z.=-s'shapdjclampingmlates arranged: Ext-each end u -Ei :-;:sheaning= .members:andL-betweenwthea ,5} mberaibingiaftenwsmds respectivglynfittewbe 

